Trump’s Twitter posts were not empty threats as the President has taken it upon himself to issue orders of killing and violence against protesters. Before he appeared in a press conference on Monday, federal police that are taking direct orders from him attacked a peaceful protest near the White House.

Source: Business Insider

The protesters were gassed and the police shot rubber bullets at them to disperse the crowd so that Trump was able to walk from the churchyard.
On top of that, his followers are also employing similar tactics to deal with the black lives movement. They are beating the protestors and also breaking into small businesses to create propaganda so that their leaders can justify their response.

On Monday, two Trump allies in Congress called all the protests “terrorists”.
Representative Matt Gaetz (R-FL) announced that the military should hunt down and kill all these Americans “like we do in the Middle East”. The tweet was instantly removed by Twitter for glorifying violence. However, the fact that Gaetz thought it was okay to tweet this without facing any consequences is quite alarming.

Source: Twitter

Senator Tom Cotton asked Trump to use the Insurrection Act so that military forces from across the US can come and give “no quarter for insurrectionists, anarchists, rioters, and looters.” This means that authorities would be able to kill all the protestors without making any arrests.
They are not even being subtle about their violent threats anymore because they know that the highest authority in America i.e the President will follow their suggestions without a second thought.